Dr. Nicole Brown’s quest to understand her misbehaving pediatric patients began with a hunch.

Brown was completing her residency at Johns Hopkins Hospital in Baltimore, when she realized that many of her low-income patients had been diagnosed with attention deficit/hyperactivity disorder (ADHD).

These children lived in households and neighborhoods where violence and relentless stress prevailed. Their parents found them hard to manage and teachers described them as disruptive or inattentive. Brown knew these behaviors as classic symptoms of ADHD, a brain disorder characterized by impulsivity, hyperactivity, and an inability to focus.

When Brown looked closely, though, she saw something else: trauma. Hyper-vigilance and dissociation, for example, could be mistaken for inattention. Impulsivity might be brought on by a stress response in overdrive.

“Despite our best efforts in referring them to behavioral therapy and starting them on stimulants, it was hard to get the symptoms under control,” she said of treating her patients according to guidelines for ADHD. “I began hypothesizing that perhaps a lot of what we were seeing was more externalizing behavior as a result of family dysfunction or other traumatic experience.”

Considered a heritable brain disorder, one in nine U.S. children—or 6.4 million youth—currently have a diagnosis of ADHD. In recent years, parents and experts have questioned whether the growing prevalence of ADHD has to do with hasty medical evaluations, a flood of advertising for ADHD drugs, and increased pressure on teachers to cultivate high-performing students. Now Brown and other researchers are drawing attention to a compelling possibility: Inattentive, hyperactive, and impulsive behavior may in fact mirror the effects of adversity, and many pediatricians, psychiatrists, and psychologists don’t know how—or don’t have the time—to tell the difference.

Though ADHD has been aggressively studied, few researchers have explored the overlap between its symptoms and the effects of chronic stress or experiencing trauma like maltreatment, abuse and violence. To test her hypothesis beyond Baltimore, Brown analyzed the results of a national survey about the health and well-being of more than 65,000 children.

“Over the past 30 years, researchers and professionals in a variety of human services and animal welfare disciplines have established significant correlations between animal abuse, child abuse and neglect, domestic violence, elder abuse and other forms of violence. Mistreating animals is no longer seen as an isolated incident that can be ignored: it is often an indicator or predictor crime and a “red flag” warning sign that other family members in the household may not be safe. We call this species-spanning interconnectedness of different forms of violence The Link.”

So states The National Link Coalition, which was created in 2008. “…Over 100 dedicated authorities, advocates and researchers representing a diverse array of animal protection, domestic violence, child maltreatment and elder abuse disciplines came together at a unique Town Meeting and National Summit in Portland, Maine.” Their “goal was to build greater awareness of how these forms of family and community violence are interconnected…and to build successful programs whereby agencies in these fields can cross-report and cross-train each other for more effective prevention of violence.”

This relatively new field of research has uncovered some grim statistics. PAWS in Washington State outlines some striking

According to research over the last 15 years, there’s no doubt now that child trauma causes toxic stress on the brains of babies and children, which causes short-term harm and long-term health consequences. So, it’s not a big surprise that the American Academy of Pediatrics issued a policy statement about the issue. What’s significant is the advice to pediatricians: Radically change how you do your job and take new approaches to protect those fragile developing brains.

The report advised pediatricians to:

Integrate a psychosocial approach into doing medicine. “Psychosocial problems and the new morbidities should no longer be viewed as categorically different from the causes and consequences of other biologically based health impairments.”

Incorporate into medical school and continuing education classes the knowledge of how childhood toxic stress affects “disruptions of the developing nervous, cardiovascular, immune, and metabolic systems, and the evidence that these disruptions can lead to lifelong impairments in learning, behavior, and both physical and mental health.” A technical report, in press, will provide more details about this.

Take an active leadership role in educating everyone — public, policy makers, educators, etc. — about the long-term consequences of childhood toxic stress.

Advocate for “new, evidence-based interventions (regardless of the provider or venue) that reduce sources of toxic stress and/or mitigate their adverse effects on young children.”